Apparatus for making cross-fin coils



Nov. 21, 1939; s. PRzyso'RdwsKl 2.181.108

APPARATUS FOR MAKING CROSS-FIN COILS Original Filed Dec. 2, 1936 9sheets sheet Inventor (Ittomeg Nov. 21, 1939. s, P z o owsm 2,181,108

. APPARATUS FpR MAKING cao'ss-Pm cons Original Filgd Dec. 2, 1936 9Sheets -Sheet 2 Inventor JibmLfi/aus l ryyborowli Otto: eg

Nov. 21, 1939. I

s. PRzYBoRowsKi APPABATUS FOR MAKING CROSS-FIN COILS Original Filed Dec.2, 1936 9 Sheets-Sheet NOV. 21, 1939. v 5, PRZYBCROWSK] 2.181,108

7 APPARATUS. FOR MAKING CROSS-FIN COILS or inal Fil'ed Dec. 2, 1936 9 d-Sheet 5 Fig. .9

ttorneg N 21, 1 s. PRZYBOROWSKI APPARATUS FOR MAKING CROSS FIN COILSoriginal Filed 1936 '9 Sheets-S beet 6 w a W Ti/g l0 Nov. 21,1939. s.FRZYBOROWSKI 2.1 8l,108

APPARATUS FOR MAKING cnoss-Fm goILs Original Filed Dec. 2, 1 36 9Sheets-Sheet 1 Nov. 21, 1939. s P Kl 218L108 APPARATUS FOR MAKINGGROSS-FIN COILS Original Filed Dec. 2, 1936 9 Sheets-Sheet 9 fnwentorJfamLS/au pr y o ow/ii Y 'QZa'Lf/d G orncg side of each other, withspacers therebetween,

Patented Nov. 21, 1939 PATENT OFFICE APPARATUS FOR MAKING CROSS-FIN ICOILS Stanislaus Przyborowski, Tonawanda, N. Y., assignor to FeddersManufacturing Company,

Inc., Buffalo, N. Y.

Original application December 2, 1936, Serial No, 113,867. Divided andthis application July 23, 1937, Serial No. 155,254

10 Claims.

This invention relates to an apparatus for making cross-fin coils, orheat exchange coils of the type having connected parallel stretches oftubing passing through transversely disposed and parallel fins.

The present application is a division of my copending application,Serial No. 113,867, filed December 2, 1936. I

The invention finds particular application to the manufacture ofcross-fin coils having integral return bends and substantiallycontinuous transverse fins, although it will beunderstood, from thefollowing description and appended claims, that the invention isapplicable to the manufacture of coils which need not include both, oreither, of these factors of thermal effectiveness.

According to the present invention, it is proposed to assembletransverse fins on tubes by pushing the fins over the tubes, or thetubes overthe fins, and, after the fins are brought to the desiredposition, to apply pressure to outstanding portions of the fins toefiect a tighter engagement with the tubes. In carrying out this phaseof the invention, the tubes may be formed with integral return bendswhich are driven through the metal of the fins, the metal in suchinstance advantageously being weakened, as by slitting, so that there isno excessive resistance to the passage of the tube through the fin. Thesubsequent pressing operation serves to restore to their originalposition the portions of the fin deformed by the transfixing operation,thus enhancing the frictional engagement between tubes and fins,

and thereby increasing the. thermal conductivity.

In order to apply the invention in a practical way, there is providedmeans for holding the fins so they may be impacted and transfixed by thetubes, which holding means may subsequently be moved over the surface ofthe fin, to operate 1 as a closing die against outstanding and deformedfin portions. For assembling simultaneously a plurality of fins on thetubes, the holding and closing members may be mounted alongthus formingwhat is commonly known as a comb, or nest, for holding as many fins asare neces- 'sary for each length of tubing. As hereinafter more fullydescribed, the herein-illustrated embodiment of the invention providesfor the housing of the die members in a pair of frames which may beopened to insert and remove the fins and tubes, but held together duringthe actual as sembling operations.

In this aspect of the invention, there is provided not only a nest butone whichis made of two or more sections which are 'so disposed as to berelatively movable, and which sections are made of elements also havingthe functions of aciation, with the fin holding nest, ofmeans'forloading the die comb with the fins. The particular meanshereinafter described takes the form of a secondary nest which may bemanually loaded and then bodily applied to the assembling comb totransfer the fins.

Other related or more specific aspects of th invention, together withthe advantages to be de-' rived from the practice thereof, will beapparent from the following description,'.in'which refer-.

ence is made to the embodiment of the invention shown in theaccompanying drawings, wherein: Fig. 1 is a perspective view of across-fin coil unit with some of the fins omitted to show the tubedisposal; Fig. 2 is a perspective view of a. fin prior to assembly onthe tubes;

Fig. 3 is a fragmentary view of a fin, drawn on an enlarged scale;

Fig. 4 is a section on the line 4-4 of Fig. 3; Fig. 5 is a section onthe line 5-5 of Fig. 3, with the fiap portions of the fin bent back; rFig. 6 is a front elevation of an assembling machine with the dieelements shown in tube assembling position;

Fig. '7 is a section on the line 1-1 of Fig. 6;

Fig. 8 is a top view of the machine, with the upper die members removed;

Fig. 9 is a section on the line 9-9 of drawn on an enlarged scale;

Figs. 10 and 11 are enlarged sectional views taken on the line I ll-l 0of Fig. 7, showing the die elements in tube receiving and closedpositions respectively;

Fig. 12- is a perspective view, more or less diagrammatic, showing onepair of die plates disposed in the tube, receiving position of Fig. 10;

. Fig. 13 is a view similar to Fig. 12, showing the .dies after movementfrom the position of Fig.

12 to closed position; v

Fig. 14 is a-top view of a loading nest for inserting fins between theseveral dies of the assembling machine;

Fig. 8,

Fig. 15 is a front view of the nest, with the handle portion brokenaway;

Fig. 16 is a perspective of a charging tool for transferring fins fromthe nest to the assembling machine; and

Fig. 17 is a fragmentary front view of the die portion of the machine,showing the loading nest positioned on the lower die unit.

- The present invention is particularly adapted to the manufacture offin and tube assemblies useful for heat transfer purposes. A specificform of such unit, as shown in Fig. 1, comprises -a continuous tube Tbent to provide parallel legs or straight stretches 20 connected byintegral loops or return bends 2|, the extremities of the coil beingdefined by terminal legs 22. Disposed transversely of the legs are aplurality of spaced parallel fins F, the specific formation of which isbest shown in Fig. 2. Each fin F is in the form of a substantiallyplane: rectangular sheet which, prior to assembly on the tubes, isformed with spaced openings 23 defined by surrounding flanges 24 whichare notched as indicated by the reference numeral 25. The metal intheplane area between adjacent pairs of openings is weakened during thepreforming operation, as, for ex ample, by slits 26 which may be.bordered by rib portions 21.

It will be understood that, in the assembled completed unit, the fins Fare disposed transversely of the tube legs, with the metal betweenadjacent legs disposed in the plane of the fin. However, since it iscontemplated'that the tube T shall be continuous, the. present inventionprovides for the weakened portions which, during the assembly operation,maybe bent out by the action of the tube loops 2| as the tubes areforced bodily through the fins. Subsequent to the positioning of thefins on the tubes, the bent portions thereof are restored to theiroriginal position. 1

. Thus, in Fig. 3, it will be observed that the fin F has asubstantially plane surface, except around the openings 23, which areflanged. In Fig. 5, it is to be assumed that the tube T has just beenforced against the fin to bend back the weakened portion in the form offlaps 28, which later are restored to the position indicated by thedotted lines in this figure. This restora tion of the flaps isaccompanied by a tightening action between the flanges 24 and the tubelegs.

In the bending back of the flaps 28 by the impacting action of the tube,the notches serve to relieve some of the bending strains at the flanges24. In forming the rib portions 21, the

metal adjacent the lips of each slit is drawn sufficiently to provide agap 29 which, during the 34, and a vertically disposed die mechanism 40,

both of which are mounted on a machine body 34 supported on legs 35, asshown in Fig. 6. The

operating elements of the die mechanism are mounted in a two-part box orholder structure, the lower'portion of this structure comprising a frame36 forming a part of the body 34. The frame 36 is provided with a base31 containing a central bearing 38 and spaced upstanding side walls 39.The side walls are connected at their front and rear faces bystraps 4|and 42 respectively, the rear strap 42 being formed-with spaced hingeknuckles 43 (Fi 8).

An upper die holder or frame 45, which is pivotally mounted on the frame36, is structurally similar thereto, comprising a base 46 having acentral bearing 41 and depending side walls 48 connected by straps 49and 51. The straps 51 are formed with hinge knuckles 52 (Fig. '7) whichare connected with the knuckles 43 by a hinge pin 54. It will thusbeunderstood that the upper and lower die holding structures may bedisposed in superimposed relation, or the upper structure may be swungaway from the lower member, as shown by the dotted lines in Fig, '7, topermit the insertion of fins in the diesand the removal of the assembledcoil unit from the machine. When in superimposed relation, the two.parts of the die holder may be secured to each other by latch members 55engaging latch lugs 55 on the upper frame 45. The latches 55 are mountedin slotted bearings 51 forming part of the side members 39, and thelatches are secured to a transverse shaft 59 which is journalled in thebearing portions 51. The latches may be readily operated to lock or topermit the opening of the upper die box by an attached operating handle61.

Each of the holders 36 and is adapted to receive complementary sectionsof a fin holding and bending structure, which, in the present embodimentof the invention, are disposed for vertical movement within the holders.As best shown in Figs. '7 and 17, the lower frame or holder 36 containsa vertically movable die shoe 53 having a central hub 64 aligned withthe bearing 38 on the fixed base 31. Secured to the upper face of theshoe 53, by means of screws 53, is a base plate 65, to which in turn issecured a group of lower die elements 60 forming in their entirety a dienest 61. The die elements are in the form of separate plates", which arespaced by interposed separators 88 to form pockets P therebetween. Asillustrated further in .Figs. 8 and 17, the plates and separators are'held together by means of relatively heavy end plates 11 and 12 andthrough bolts 13, The plates 1| and 12 are tapped to receive screws 14(Fig. 17) which rigidly secure the die assembly to the base plate 55.

The upper complementary assembly in the holder 45 is of similar generalconstruction, except for the contour of the die elements 10 themselves,which will be hereinafter more fully described. As the structure isotherwise identical for all practical purposes, further descriptionthereof will therefore not be made. It will be understood, however, thatthe combined fin spacing, holding, and bending units are mounted in eachholder, and they may be mounted in superimposed relation and are movablebodily toward each other.

It may here be explained that the fins are inserted in the pockets Pbetween the die members 68, whereupon the upper frame 45 is brought'into the ;closed position shown in Fig. '7, to engage the protrudingedges of the fins. At such time, the dies 68 and 10 are spaced, as shownin Fig. '7, and also in Figs. 10 and 12. It is at this point in theoperation that the tube is forced through the bank of fins, deformingthe impacted metal thereof as shown in Fig 10. Subsequently the dieelements 58 and 10 are moved closer together, as shown in Figs. 11 and13, to restore as much as possible the fin metal to its originalposition.

The actuating means for the die nests herein takes the form, of likepneumatic cylinders I6, which, as best shown in Figs. 6 and '7, aremounted on the bases 31 and 46 of the upper and lower die holdingframes. The piston rods 11 of each cylinder project through the alignedbearing openings in the frames and are secured in the hubs 64 of the dieshoes 63. extension or retraction of the pistons in the cylinders I7,and hence the spacing of the die ele;

ments 68 and I0, is controlled by a single valve I9 accessibly locatedon the machine body. As

the nature of such control valves is well under-' stood, and the precisedetails of the connections between the valves and cylinders form no partof the present invention, further description of the mechanism istherefore deemed unnecessary.

The die elements 68 and I shown in Fig. 7 are also illustrated in Fig.12, wherein itwill be observed that the lower die 68 is formed with aplurality of vertical notches BI to define die fingers 82 and interposedholding fingers 80 projecting abovethe tops of the fingers 82.' The. dieI0 is formed with identical and vertically'aligned die fingers 82aseparated by relatively Wide notches and 12, that the holding fingers 80are s uificiently,

8Ia which receive the ends of the holding fingers 80. The opposedhorizontal surfaces of the die fingers 82 and 82a form complementarybending die portions 83 and 83a, while the corners are formed withquadrantal notches 84 and 84a adapted to engage the flanges 24 of thefins F. The portions 83 and 83a are also formed with rounded or pointedcrests 85 and 85a, as best shown in the cross-sectional view, Fig. 10.The holding fingers 83 are likewise formed with crests 86 which permitof ready insertion of the fins in the die bank or comb 60, and alsofacilitate The holding fingers 80 are sufiiciently spaced from the upperdie fingers82a to permit insertion therebetween of upper and lowerholding bars 87 and 98', extending transversely of and beyond the diebanks, and held in a relatively fixed position by .means hereinafterdescribed. These bars serve to support the fins interposed between thedie fingers and to retain them in fixed position during the assemblingoperations.

It will be noted, by further reference to Figs. 10

spaced to permit the passage of an integral return bend 2| of. the tubeT. During the passage of the tube T through the fins disposed in thealigned pockets P of the adjacent dies 68 and I0, the portions of finimpacted by the tube bends are bent over the horizontal portions of thedies 82 and 82a to form the flaps 28. It will be observed that thepockets P receive the fins in a fairly snug fit, sothat during thisoperation the vertical front faces of successive plates act as abutmentsto prevent collapse of the fiii bodies.

After the tube T has been inserted through the fins, the dies arebrought together to the positions shown in Figs. 11 and 13, thus causingthe flaps 28 to be restored to their original position. During thisoperation, the quadrantal die portions 84, 84a engage the bent portionsof the flanges 24 and restore them to their cylindrical shape in tightengagement with the legs 20 of the tube T.

The tube impelling unit 30 comprisesv a pneumatic cylinder 95 (see Figs.6, 8, and 9) which is The simultaneous horizontally disposed on andsecured to a head bracket 96 located at the right hand extremity of themachine body 34. The bracket is formed with horizontal slide rails 98for receiving a carriage or cross head I00 formed with complementaryslide bearing portions WI. The piston rod I02 of .thecylinder 95 issecured in a hub I05 formed on the cross head I00 so that, uponactuation of the piston, the head is caused to be moved toward the diemechanism 40.

' The vertical face I05 of the cross head I00 is formed with spacedsockets I06 (Fig. 9) adapted to receive the return loops 2| of the tubeT when the head is in withdrawn position, as indicated by the dottedlines in Fig. 8. The terminal legs 22 of the tube T project throughslots I08 formed in the top of the cross head I 00, so that their openends may abut extension plates I09 connected to the'cross head by studsIII for'movement therewith. The extension plates may be provided withdowels II 2 for entering the open tube ends to prevent lateraldisplacement during the assembling operations.

The cross head I00 may also be provided with additional slots IBM toaccommodate coils having varying numbers of tube legs 2|, therebyadapting the apparatus to the manufacture of Springs H6, secured'to thearm H5 and the bracket. 96, normally retain the bar H5 in positionagainst the face of the bracket 96, but permit the bar to swing toan'inoperative position when struck by the head I00 at the end of itsforward travel.

From the invention as thus far described, it

-will be appreciated that after fins are disposed between the diemembersin the mechanism 40,

the tube T, mounted on the cross head I00, is driven through the finsand between the dies, and subsequently the dies are operated to forcethe fin metal back to its original position. As

this transfixing of the fins by the tubes, and the straightening of thefins, are both rather severe actions, it isadvantageous to provide theholding bars 81 and 88 heretofore referred to.

The holding structure for the bars 8'! and 89 is best shown in Figs.,6,9, and 1'7. Disposed at either'end of the die bank are cross bars 89which are adjustably secured to the adjacent frames .by screws 9|. Thebars 81 and 88 are so spaced as to engage the fins F along their upperand loweredges when the upper head 45 is brought to closed position,thus firmly holding the fins against displacement.

In order to insert fins in the spaces or pockets P between the dieelements .68, the upper head 45 is swung back, as shown by the dottedline position in Fig. '7, thus exposing the lower die as- 5 tween thepockets I23 is the same as the center to center distance of the pocketsP, although the width of the pockets I23 is somewhat greater, so thatthe fins F may be more readily inserted in the auxiliary nest with aloose fit. Gauges I26 are secured to the top of the nest I20 at eachside thereof and are positioned to serve as side guides during theinsertion of the fins in the pockets I23. Horizontal alignment of andsupport for the fins in the nest I20 is obtained by a wire frame I21having spaced legs I23 which my extend through aligned apertures Iformed in the plates IZI. Dowels I3I, projecting from the lower cornersof the nest I20, are adapted to enter holes. I32 (Fig. 1'?) in the heavyend plates 20 II and I2 of the lower die assembly, when the nest I20 isplaced thereon.

When the auxiliary nest I20 is positioned on the lower die bank 60, asillustrated in Fig. 17, the wire frame I21 is withdrawn, and the con- 25tained fins F thus are free to fall into the pockets II9, being readilyguided thereinto by the beveled edges 86 of the holding fingers 80.As'there is too much frictional resistance to permit the fins to fallfreely to the bottom of the pockets P,

a thrust fixture I30 (Fig. 16 is provided. This member has spaceddepending portions I33 which are adapted to engage aligned slots I34formed in the nest plates I2I. when the fixture I30 is thrust downward,the underlying fins F are forced 35 toward the bottom-of the pockets P.The upper die unit may then be swung into closed 'position, the upperbars 01, forcing thefins to their proper position, if they are notalready fully located. During such closing action, the upper 40 dieelements I0 embrace the upper portions of the fin, thus bringing theparts into the relative positions heretofore described in connectionwith Fig. 12.

' From the foregoing description, it will now be understood that, afterthe fins F are disposed between the die elements in the pockets II9, theclosing and securing of the upper head 45 firmly holds each fin betweenadjacent pairs of dieelements 68 and I0, so that the tube impell- 5 ingmechanism 30 may be operated to force the tubes through the fins. Duringthe tube assembling operation, the leading loops 2| engage the weakenedportions of the fins and act as bending or piercing dies to force theflap portions 28 of the fins rearward about the horizontal bending dieportions 83 and 83a, as illustrated in Fig. 10.

The fins F are thus progressively transfixed by the tubes until theleading tube loops completely pass through the entire fin assembly, atwhich 0 time the head I00 is fully extended from the cylinder 95. Thevalve I9 is then operated, to force the various cooperating die plates68 and III together, and to the position shown in Figs. 11 and "13.During this action, the die surfaces 03 and 03a engage the flaps 28 torestore them. to their original coplanar position. In order tocompensate for the inherent resiliency of the fins, the dies are soformed as to induce a slight overbending of the flaps 20, which occursnear the end of the die strokes when the portions 03, 03a contact theinclined surfaces of the ribs 21 and force the flaps a slight distanceto the right (Fig. 11). Simultaneously with the above-described bendingoperation,the quadrantal bending dies 04 and 84a engage the flanges 24of the fins and restore them to their original cylindrical character.The relation betwen the die plates is such that, during the die closingmovement, the flanges 24 are forcibly applied to the legs 20 of the tubeT to effect a strong frictional engage- '5 ment. Upon reversal of thevalve 19 to separate the dies 63 and I0, the frame 45'may be unlatchedand swung back, whereupon the assembled fin and tube structure may beremoved. If desired, 10 the unit may be applied in practical use as itcomes from-the machine, or it may be clipped in solder to seal alljoints and increase the thermal efliciency.

In some coil structures, there maybe experi- 5 enced some difiiculty inpreserving loop alignment during assembly. In such event, it isadvantageous to employ a tube stop I40, as illustrated in Figs. 8 and17. This member is slidably mounted on the left hand side wall of thelower 20 frame 36 by screws I which engage in slots I 42 formed therein.The right hand face of the stop I40 is formed with sockets I43 forreceiving the leading tube loops 2| after the tube has been forcedthrough the dies. Horizontal movement 25 of the stop I40 in thedirection of the tube unit is obtained by a cam mechanism including camsI44 mounted on an operating shaft I45 journalled in bearings I46. I

The stop maybe employed to limit the move- 30 ment of the tube loops,and also may be operated .by the cams to-force the tube T slightly tothe right, thereby springing'the accompanying fins in their pockets fora slight alignment correction. 35 I It will be appreciated that thepresent invention thus provides a novel and effective method of formingfin and tube assemblies, as well as a novel machine for assembling finson tubes.

While the inv'ention has been described with ref- 4 erence to a singleembodiment, and in the form of a complete machine, it will be understoodby those skilledin the art that the objects and advantages of theinvention may be attained by other forms of apparatus or modificationsin procedure. It 45 is therefore intended that the invention shall bedeemed commensurate with the scope of the following claims.

I claim:

1. An apparatus for holding apertured fins for 50 tion to a position toclear the other nest for the reception of fins, and means for moving oneof the nests to extreme inner-and outer opposed po-- sitions, said lastmentioned nest including dies, the outer position spacing the nests toclear the o5 tube deflections as the tubespass through .the fins and themovement to the inner position moving the dies to bend the aforesaid fin.portions bapk toward the planes of the fins.

2. A fin and tube assembly apparatus of the 70 type wherein U tubes arepushed through fins with the U end first and the fins have pairs ofopenings, for pairs of tubes, connected by a slit to enable the U of thetubes to be pushed through other portions of the fins, each nestincluding a plurality of fin spacing means, one of said nests amigos J-frame movable with respect thereto, a lower fin nest for holding-aplurality of fins in spaced relation and supporting the lower portionsof thefaces thereof movably mounted on said lower of fins and to aclosed fin supporting position,

means for locking said frame in closed position, said nests, due totheir movable mounting beingcapable of movement in oppositedirections-to space the adjacent edges of their resp'ectivespacingplates sufiiciently to clear the U of the tubes as they are pushed intothe fins to seat the tubes in the openings of the fins, means forholding the I opposite ends of the tubes and pushing the tubes into thefins, the fins after insertion of the tubes having face portionsintermediate each pair of openings bent out of the plane of the fins toform a slot and means on each frame for moving said nests together tomove the spacing plates along the faces of the fins to bend the bent'portions back toward the plane of the fins to narrow the slots.

3.'A fin and tube assembly apparatus of the type wherein U-tubes arepushed through fins with the U-end first and the fins having pairs ofopenings, for pairs of tubes, connected by a slit to enable the U of thetubes to be pushed through the fins, comprising a frame, said frameinclud-' ing a first nest and a second'nest, one of said nests beingmovable relative to the other, one of said nests being capable ofsupporting at least a portion of a plurality of fins and spacing saidfins, the said second nest capable of spacing being capable of at leastthree positions relative to the other nest, the first of said positionsbeing one in which the two nests are relatively remote from each otherto permit insertion of the fins, the second position being intermediatewith the fin spacing means of each nest relatively close to each otherbut yet in spaced relation. and a third position in which the finspacing means.

of each nest are closest together,.means for holding said movable nestin said intermediate position with the respective spacing means of thenests spaced suificiently to clear the U of the tubes as they are pushedinto the finsto seat the tubes on the apertures of the fins, the finsafter insertion of the tubes, having fa'ce portions intermediate eachpair of openings bent at an angle to enlarge the slits, and said meansbeing operable to move the nests togetherfrom the intermediate positionto the third position to relatively move the spacing means along thefaces of the to-bend the bent portions-back to narrow theenthereceptionofabankoftubesastheyare passed through the fin apertures,the tubes having a bent portion and wherein the finshave provision foraportion thereof adjacent the aperturestobebentoutoftheplaneofthefintoclear the bent portion, said apparatus comprising opposed nests, thenests including combined 1 113 and die members, said members beingpmvidedwith a plurality of aligned and spaced fingers whose adjacentedges are each formed with 4 die edges adapted, when said plates aremoved contiguous curved and straight die formations,

' the nests holding the fins in spaced parallel relation at oppositesides of the apertures, means mounting one of said nests for movementfrom its opposed position to a position to clear the 5 other nest forthe reception of fins, and means 7 for moving one of the nests toextreme inner and outer opposed positions, the outer position spacingthe nests to clear the tube bent portions as the tubes pass through thefins and-the movement to the inner position involving the movement ofthe die members to bend the aforesaid fin portions back toward theplanes of the fins. 5. In a machine for assembling a plurality of spacedtransversely disposed fins with tubing, 15 a fin holding nest composedof a plurality of regularlyspaced plates adapted to hold fins betweensuccessive plates, a second fin holding nest also composed of aplurality of plates spaced the same as the first set of plates, framemeans for holding the plates in superimposed relation with the plates inone nest aligned-with the plates of.

the other nest in a series of common planes each including a plate fromeach nest, means for holding the plates of one nestwith their edgesslightly spaced from the edges of theplates of the other nest, toprovide a gap between the two nests through which tubing may be movedtransversely of the plates and fins adapted to be held therebetween, theadjacentiedges of the aligned plates in each nest being formed with workengaging die portions, and means for releasing said holding means andmoving the plates toward each other through their common planes and intothe gap and into close juxtaposition, whereby the die portions maycontact the work to deinto close juxtaposition, to deform metal of thefins at the 'joints between the fins and the tubfor the nests'havingfingers, said fingers being so formed with quadrantal dieportionsconnected by substantially straight die portions, adapted, when-saidplates are moved into close juxtaposition, to deform the metal of thefins both at the joints between the fins and tubes and between asadjacent tubing stretches.

10. In the machine of claim 5, plate members formed with a plurality ofspaced fingers having die formations at the edges thereof, at least somei of said plate members being additionally formed 10 with holdingfingers alternating with the die fingers'.

S'IANISLAUS

